ZyXEL Communications Prestige 724, Руководство пользователя

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Prestige 724 G.SHDSL CSU/DSU
F Virtual Circuit Topology
Appendix C
Virtual Circuit Topology
ATM is a connection-oriented technology, meaning that it sets up virtual circuits over which end systems
communicate. The terminology for virtual circuits is as follows:
z Virtual Circuit A path between points in a network
z Virtual Path A bundle of virtual channels
z Virtual Channel Logical connections between end stations
Diagram 2 Virtual Circuit Topology
Think of a virtual path as a cable that contains a bundle of wires. The cable connects two points and wires
within the cable provide individual circuits between the two points. In an ATM cell header, a VPI (Virtual
Path Identifier) identifies a link formed by a virtual path; a VCI (Virtual Channel Identifier) identifies a
channel within a virtual path. The VPI and VCI are identified by, and correspond to, termination points at
ATM switches on a virtual circuit. Your service provider should supply you with VPI/VCI numbers.